Azo dye.



UNITED STATES PATENT OFFICE.

MYRTIL KAHN, OF ELBERFELD, AND RICHARD KOTHE, OF VOHWINKEL, NEAR ELBERFELD,

GERMANY, ASSIGNORS TO FARBENFABRIKEN VORM. FRIEDR. BAYER & 00., OF ELBER- FELD, GERMANY, A CORPORATION OF GERMANY.

AZO DYE.

Specification of Letters Patent.

Patented Sept. 3; 1907.

Application filer, Tune 5, 1907. Serial No. 377,325.

To all whom it may concern:

Be it known that we, MYRTIL KAHN and RICHARD Ko'rnn, doctors of philosophy, chemists, citizens of the German Empire, residing at, respectively, Elberield and Vohwinkel, near Elberield, in the Kingdom of Prussia, Germany, have invented new and useful Improvements in new Azo Dye, of which the following is a specification.

We have found that a new and valuable azo dyestuff is obtained by combining the diazo compound of 4- chloro-2-amin0phenol-G-sulionic acid with l-naphthol- 4-sulfonic acid.

In carrying out the new process practically we can proceed as follows, the parts being by weight: 22.4 parts of 4-cliloro-2-aminophenol-G-sulionic acid are diazotized in the usual manner by means of hydrochloric acid and 7 parts of sodium nitrite. The diazo compound is then poured into a solution of 25 parts of the sodium salt of l-naphtholl-s'ulfonic acid, to which suflicient sodium carbonate has been added to maintain the reaction alkaline throughout the whole process. The dyestuff is salted out, pressed and dried. It is, after being dried and pulverized, in the shape of its sodium salt a dark powder soluble in water with a reddish-violet color and in concentrated sulfuric acid with a reddish-violet color. By reduction with stannous chlorid and hydrochloric acid 4-chloro-2- aminophenol-G-sulfonic acid and 2-a1nino-1-naphthol- 4-sulionic acid is obtained. The new dyestuff dyes wool from acid baths a bluish-red shade which is changed to a fast bluish-violet when chromed after dyeing.

Having now described our invention and in what manner the same is to be performed, what we claim as new and desire to secure by Letters Patent is In testimony whereof we have hereunto set our hands in the presence of two subscribing witnesses.

MYRTIL KAI-IN. RICHARD KOTI-IE.

[1... s.] [n s.]

Witnesses t O'r'ro KONIG,

AUG. LANDSIEDEL. 

